1. Field of the Invention
The present invention relates to a tactile feedback apparatus applicable to a remote control robot system, and more particularly to an improved tactile feedback apparatus using electromagnetic attraction for a remote control robot, wherein tactile data obtained during operations between grippers attached to a robot arm of an externally controlled robot and the grippers' targets are effectively transferred to an operator stationed in a central control room, thereby enabling the robot system to effectively carry out a variety of sophisticated tasks.
2. Description of the Prior Art
An industrial robot directly controlled by a human operator stationed at a distance therefrom performs highly complicated tasks, while positively coping with variable external environments. Thanks to its excellent workability, such a remote control robot is widely applied to industrial fields throughout most industrialized nations in the world where environmental obstacles do not allow an easy access for men thereto, and it carries out such objectives as: radioactive material handling tasks in an atomic reactor; deep sea probes, exploitations and experiments under high water pressure; repair work of a satellite breakdown in outer space; and remote medical treatment.
As shown in FIG. 1, a general remote control robot system is operated under the provision of optical and auditory data from its ambience. Recently, in order to provide for more efficient control of the robot, additional tactile application is carried out with regard to its arms and hands. However, owing to deficiency in tactile information applied thereto, the performance of sophisticated tasks by robot still experiences obstacles.
Referring to conventional tactile feedback apparatus applicable to a remote control robot system, there are known the "Teletact II" system of ARRC/Airmuscle Ltd. in Britain and the "Tactools XTT1" system of Xtensory Company in America.
The Teletact II system is operated through the use of air pressure, and a proportionally expandable small air bag is attached thereto. An electronic controller and a compressor are employed to deliver pressure. Each tactor is 15 mm in diameter, and when fully swollen, its contact area becomes 100 mm.sup.2. One tactor can be attached to each of the operator's finger knuckles. The maximum output per tactor becomes approximately 8.4 gf/mm.sup.2.
The Tactools XTT1 system employs a shape memory alloy, wherein its composition adapts an on/off switching state so that a successive control of its output is not possible. Each tactor measures 9.times.20.times.5 mm.sup.3, and accordingly only one tactor can be mounted on each finger. An output is produced on the skin of the uppermost knuckle of each finger by one 1 mm diameter pin is attached on each tactor.
However, in order to carry out such a sophisticated remote control, a tactile feedback apparatus required in a practical remote control robot system should satisfy the following conditions.
First, the respective devices provided in the tactile feedback apparatus should be distributed in an array. That is, in order to practically similate the tactility of human, a tactile feedback device should be densely populated in a maximal vicinity to a spatial resolution of 2 mm that denotes a minimal distance difference, by which two kinds of force can be distinguishable when operated with each other spaced by a distance in the similated skin.
Secondly, in order to provide the operator sensations of a contact or a material slippage, there should be appropriately carried out an array unit feedback control between respective tactile feedback devices.
Thirdly, human force resolution (or sensitivity) is expressed as 2 gf(gram force) and provided with a discontinuous recognition, so that the tactile feedback apparatus enables its force to be under a linear control by a force resolution unit.
Fourthly, side effects that may occur due to the attachment of the tactile feedback apparatus should be overcome or minimized. A product employing an air pressure may generate noise, whereas a vibration-transmitting product may cause weariness when the operator is mounted with the products for a long time. Therefore, such side effects should be corrected, and operational errors and interference caused by the mounting also should be overcome.
However, a tactile feedback apparatus satisfying the above-described requirements has yet to be developed.